COMBINED TENSION AND SHEAR LOAD
Parabolic
Equations β NV
= β ζ N + βζ V ≤ 1 . 0 ( continued )
Equations ACI 318-19 Chapter 17 Provision Comments for PROFIS Engineering
β NV
= β ζ N + βζ V ≤ 1 . 0
Excerpt from Table 17 . 5 . 2 showing the tension failure modes considered in ACI 318-19 anchoringto-concrete provisions .
Table 17.5.2 — Design strength requirements of anchors
Failure Mode Single Anchor
Individual anchor in a Group
Steel strength in tension ( 17.6.1 ) ϕN sa ≥ N ua ϕN sa
≥ N ua , i
Concrete breakout strength in tension ( 17.6 . 2 ) ϕN cb
≥ N ua
Pullout strength in tension ( 17.6.3 ) ϕN pn ≥ N ua ϕN pn
≥ N ua , i
Concrete side-face blowout strength in tension ( 17.6.4 )
Bond strengh of adhesive anchor in tension ( 17.6.5 ) ϕN sb
≥ N ua
ϕN a
≥ N ua
Anchor Group
Anchors as a group
ϕN cbg
≥ N ua , g
ϕN sbg
≥ N ua , g
ϕN ag
≥ N ua , g
Part 4 of the PROFIS Engineering report shows the ratio of factored shear load ( V ua
) to shear design strength ( ϕV N ) via the parameter β V
. For the example below , concrete edge failure in direction x + is the governing failure mode for shear because it has the highest utilization ( β V
= 60 %).
4 Shear load Load V ua
[ lb ]
Capacity ϕV n [ lb ]
Utilization
β N
= V ua / ϕV n
Status
Steel strength * 1,500 4,540 33 OK
Steel failure with lever arm *
Pryout ( bond strength controls )*
Concrete edge failure in direction x + **
* highest loaded anchor ** Anchor group ( relevant anchors )
N / A N / A N / A N / A
6,000 52,765 12 OK
6,000 10,080 60 OK
Excerpt from Table 17.5.2 showing the shear failure modes considered in ACI 318-19 anchoring-toconcrete provisions .
Table 17.5.2 — Design strength requirements of anchors
Failure Mode Single Anchor
Individual anchor in a Group
Steel strength in shear ( 17.7.1 ) ϕV sa ≥ V ua ϕV sa
≥ V ua , i
Anchor Group
Anchors as a group
For the examples above , PROFIS Engineering would perform the combined |
interaction check using the parabolic interaction equation as follows : |
|
β NV
= ( β N ) 5 / 3 + ( β V
) 5 / 3
|
check : β NV < 1.0 |
= ( 0.51 ) 5 / 3 + ( 0.6 ) 5 / 3 = 0.752 |
check : 0.752 < 1.0 |
OK |
Reference the PROFIS Engineering design guide section on the trilinear interaction equation for additional information about PROFIS Engineering interaction calculations .
Concrete breakout strength in shear ( 17.7.2 )
Concrete pryout strength in shear ( 17.7.3 ) ϕV cb
≥ V ua
ϕV cp
≥ V ua ϕV cbg
≥ V ua , g
ϕV cpg
≥ V ua , g
340 NORTH AMERICAN PROFIS ENGINEERING ANCHORING TO CONCRETE DESIGN GUIDE — ACI 318-19 Provisions